1. Field of the Invention
This invention is related to a dial matching device for a combination lock, in particular, a dial matching device that helps the user to more accurately identify the corresponding locations of all the dials for unlocking the combination lock,
2. Description of the Related Art
A combination lock is a locking apparatus utilizing dials which must be adjusted to the pre-designated locations of preset numerals or symbols for unlocking the combination lock.
The conventional combination lock usually includes indication arrows, symbols, grooves or protrusions as the dial matching device, which is referred to as “dial matching indication unit” hereinafter, on one or both sides of the parallel dials of the combination lock to identify the locations for matching the dials with the combination. The user adjusts the dials of the combination lock to the locations for matching the dials with the preset combination with reference to the dial matching indication unit so as to unlock the combination lock. In other words, as long as each of the dials is accurately matched with the preset numeral or symbol at the location indicated by the dial matching indication unit, the combination lock may be unlocked
Generally, the “dial matching indication unit” is provided only adjacent to the outermost dial(s), that is, only the outermost dial(s) may be directly identified by the adjacent dial matching indication unit. Nonetheless, the dials in the middle, or those not adjacent to the dial matching indication unit, may still be checked by visually extending the identification direction pointed out by the dial matching indication unit, so that the user may complete the dial matching process. Such kind of dial matching indication unit has been used in the combination lock for a long time.
However, such a dial matching indication unit is not an ideal solution for the combination lock. Usually, the dial matching indication unit is not very apparent to the user and thus, some drawbacks may occur. For example:                1. When the grooves or protrusions are used on the surface of the combination lock as the dial matching indication unit, if the depth or height thereof is too small, the visual effect for identification may not be significant enough; on the other hand, if the depth of the grooves is too large, dust may be accumulated therein; if the height of the protrusions is too large, they may appear awkward.        2. If the dial matching indication unit is printed on the surface of the lock or in the form of a sticker, they are easily damaged during the usage of the lock and may become unclear or even disappear and thus, the identification function thereof is deteriorated.        3. Even if a user knows that the designated combination number of the dials must exactly match with the indication unit in order to unlock the locks, combination locks usually allow a minute amount of displacement such that the locks still cannot be unlocked even if the indicating unit has pointed to the side edges of the designated combination number with excessive displacement.        